1. Field of the Invention
The present invention relates generally to a system and method for animation of an object displayed via a computer system. More specifically, the present invention relates to a method and system for animating a character utilizing joints which allow more natural animation.
2. Background
As computer games and internet interaction quickly gain in popularity, the use of animated characters are becoming more prevalent. Characters can be animated through several ways. One way is to utilize a constant feed of video into a computer system. Another way is to utilize a series of static pictures of the character, each still picture being changed minutely from the previous picture to simulate motion. However, these conventional methods are very costly and can be highly labor intensive.
One possible solution which has been attempted is to utilize a single still image of a character and move a portion of the still image, such that the character appears to move. However, current conventional techniques have typically been unable to simulate natural motion. A very limiting problem with the conventional techniques is that the dimensions of the portion of the character which is being moved will typically change as the portion is being moved, thus causing a highly unnatural motion.
Another possible solution might be to compile an image of a character and move individual pieces of the character. For example, if a character is to resemble a person, then the character may be compiled from multiple pieces, including a piece representing a body, a piece representing a head, a piece representing an upper arm, a piece representing a lower arm, and a piece representing a hand. To simulate motion, one or several of the pieces of the compilation can be moved. A problem arises, however, when a piece is moved which has more than one connection. For instance, when an upper arm piece is moved, then the upper arm of the character moves, but the lower arm and hand remain in their fixed positions. Again, the result is a highly unnatural motion of the character. FIG. 1 is an illustration of a conventional method for making a single image of a character animatable. FIG. 2 shows a character 10 in its original position with a torso 14, arms 12A-12B, and joints 16A-16B. When a portion of the character is moved, then the moving portion is projected along the angular rotation of the movement. For example, if the arm 12A of FIG. 2 is moved "down", then the top and bottom edges 18A-18B of the arm 12A are rotated "down". The resulting moved arm 12A' has edges 18A' and 18B' which are closer to each other in width than the edges of the arm 12A prior to movement. Thus, the dimensions of the portion which has been moved in relation to the remaining portion of the character have changed in such a way as to change the integrity of the geometric structure.
Accordingly, what is needed is a system and method for animating a character being displayed via a computer system which can simulate a more natural motion. The present invention address such a need.